Field
The present invention generally relates to a method and apparatus for feeding joining elements to a joining tool.
Description of Related Art
It is known in the field of joining technology to perform joining connections using joining elements. These methods comprise, for example, the joining of joining elements onto workpieces, the joining elements being used in this case frequently as anchors for further fastening means. Joining methods of this type are known in the form of stud welding, stud adhesion or thermoplastic stud joining. Here, the studs can be rotationally symmetrical joining elements, but can also be irregularly shaped anchors.
Furthermore, it is known to connect at least two workpieces to one another by means of joining elements. Methods of this type comprise, for example, riveting methods, such as the punch riveting method.
Joining methods of this type have been established in the field of vehicle technology for some years, in particular in body construction.
It is possible in general to carry out these joining methods by hand. Here, joining tools which frequently have a pistol-like grip are guided by hand. In mass production usage, however, it is preferred to move the joining tools by means of a programmable handling unit, such as a robot. In this case, it is likewise preferred if the joining elements are fed to the joining tool which is fastened to a robot arm. To this end, it is known to connect the joining tool to a feed device via a feed tube. Here, a proven method for feeding joining elements comprises feeding the joining elements through the feed tube by means of compressed or blown air.
A further known system connects the feed device to a docking station via a feed tube. In this case, there is a buffer store on the joining tool for receiving a plurality of joining elements. In order to fill the magazine, the joining tool is moved to the docking station and is docked there. Here, the docking takes place in such a way that both an outlet connection in the region of the docking station and an inlet connection of the buffer store are opened mechanically by the docking operation, in order to produce a continuous connection between the feed device and the buffer store. The outlay required here for mechanical actuating elements and gear mechanisms is considerable. Furthermore, docking and undocking is a relatively time-consuming process.